2,4-Chlorodinitrobenzene

The nature of the Janovsky s colour reaction is not sufficiently understood. Reitzenstein and Stamm [55] were the first to try to establish the structure of the compounds formed. They were able to isolate from an acetone solution a brown product (IV), resulting from the reaction of 1,2,4-chlorodinitrobenzene with the enolic form of acetone ... 

For preparing 1,2,4-chlorodinitrobenzene of high purity,/ - chloronitrobenzene should be used as starting material since mixtures of o- and p- chloronitrobenzenes yield mixtures of two dinitro-isomers, namely, 1,2,6- and 1,2,4,-. The corresponding reactions are shown in the diagram on p. 465. 

A different approach leading to thianthrene derivatives starts from 0-ethyl or 0-isopropyl dithiocarbonate 394, when heated with chlorodinitrobenzene derivative 59 provided intermediate 395, the compound having all features necessary for denitrocyclization reaction to the final product 396, which was the only isolated compound (Scheme 61). Its structure was assigned by X-ray crystallography (77JOC2896). 

Nitration of dinitrophenol. This is a multistage process. First chlorobenzene is nitrated to chlorodinitrobenzene as shown schematically below ... 

The residue left from conversion of the chloro to the fluoro compound exploded during distillation at 1.3 mbar [1], Reheating the residue from distillation caused violent decomposition [2], Traces of an aci-nitroquinonoid species (structure str02, p. S1-S7) may have been formed in the chlorodinitrobenzene-potassium fluoride reaction system [3],... 

Since methylamine prepared from methyl alohol and ammonia has become available commercially, the preparation of tetryl from dinitromethylaniline obtained from chlorodinitrobenzene and methylamine has been widely used. 

Dinitrd iethylanilme is produced by the reaction of chlorodinitrobenzene with methylamine in the presence of sodium hydroxide. A solution is prepared consisting of 300 1. of water, 1140 1. of 35% aqueous sodium hydroxide solution and 1225 kg of 25% aqueous methylamine solution. This solution is added over a period of 12 hr to a vigorously stirred suspension of 2000 kg of chlorodinitrobenzene in 1350 1. of water heated to 95-100°C. 

This product has been prepared both by the nitration of N-n-butylaniline and by the action of n-butylamine on chlorodinitrobenzene followed by nitration of dinitro-N-n-butylaniline. 

It is most conveniently prepared by the interaction of ethylenediamine and chlorodinitrobenzene, followed by the nitration of the amine so obtained ... 

Pentryl has been prepared by two methods (a) from aniline and ethylene oxide (according to Herz [80]) and (b) from chlorodinitrobenzene and ethanolamine (according to Moran) with the subsequent nitration of N-hydroxyethylaniline or its dinitro derivative ... 

According to Clark [81] this compound is obtained by the nitration of tetra-nitrodiphenyl-/ -hydroxyaminoethane (II) which is formed as a by-product when preparing dinitrotriphenyl-/ -hydroxyaminoe thane from chlorodinitrobenzene and ethanolamine (see above, p. 71). 

AN 88 to 91, DNB or ch loronaphthalene 4 to 6 and wood flour 4 to 6%. It was packed in paper cartridges waterproofed by means of cere sine. A detonator contg 1 g of 95/5— MF/KClO, mixt was used for its initiation. ColverfRef 2) gives the following compn for Amvis Powder AN 90, chlorodinitrobenzene 5 and wood meal 3%... 

It is noteworthy that in more recent studies on nitrocellulose decomposition (Wil-fong, Penner, Daniels [66]) similar results and values for the activation energy have been obtained, namely E = 46.67 kcal/mole in the temperature range 84 to 162°C. R. D. Smith [67] has examined the thermal decomposition of nitrocotton of 11.8% N in such high-boiling substances as chlorodinitrobenzene, nitronaph-thalene, benzophenone, within the temperature range 165-200°C and determined the values ... 

Note. (1) It is advisable to recrystallise the commercial chlorodinitrobenzene from ethanol m.p. 51-52 °C. 

Note. The chlorodinitrobenzene must be handled cautiously (use disposable gloves). If any touches the skin, wash it with industrial spirit and then copiously with water. 

The nitration of chlorobenzene was first mentioned in 1862 by Riche [6], Later the reaction was studied by Sokolov [7] and Holleman and de Bruyn [8], Junglleisch [9] was the first to describe the method of preparation of chlorodinitrobenzene from o- or p- chloronitrobenzene. Laubenheimer [10] investigated the products of the nitration of m- chloronitrobenzene, and Ostromyslenskii [11] determined the structure of the products obtained by Jungfleisch, i.e. of 1,2,4- and 1,2,6-chloro-dinitrobenzenes. Finally in 1894 the Griesheim factory reported [12] on a method of preparing chlorotrinitrobenzene by direct nitration of chlorobenzene. 

Among the six chlorodinitrobenzenes known, the 1,2,4- and 1,2,6-isomers are the most important as they are the principal products of the nitration of chlorobenzene. l-Chloro-2,4-dinitrobenzene results from the nitration of o- and p- chloronitrobenzenes and l-chloro-2,6-dinitrobenzene from the o- isomer. Apart from these, the 1,3,4-isomer, which forms in the nitration of m- chloronitrobenzene, is of some importance. 

Chemical properties. A chlorine atom ortho or para to a nitro group is especially reactive and is readily substituted. Numerous examples of such reactions, utilized in the preparation of explosives, are given later in the descriptions of preparation methods for dinitrophenol, dinitroanisole, hexanitrodiphenylamine, hexanitro-diphenyl sulphone, dinitroaniline, tetryl, etc. Chlorodinitrobenzene reacts with sodium sulphide and sulphur to yield sulphur dyes. The action of sodium disulphide results in the formation of tetranitrodiphenyl sulphide (p. 554). 

When treated with KHS in alcoholic solution chlorodinitrobenzene yields dinitrothiophenol ... 

Chlorodinitrobenzene reacts with pyridine to form dinitrophenylpyridinium chloride (Vongerichten [19]) ... 

When using chlorodinitrobenzene in the manufacture of explosives, the products obtained from it (e.g. dinitroanisole, dinitrodiphenylamine) are nearly always subjected to further nitration. Both the 1,2,6- and 1,2,4-isomers then yield the same trinitro derivative, l-chloro-2,4,6-trinitrobenzene. In such cases separation of the isomers and the preparation of highly pure 1,2,4-isomer is not necessary. 

There are cases, however, where the presence of the two isomers makes process control difficult, i.e. when the process is controlled by determining the melting point of the product. Then o- and p- chlorodinitrobenzenes are separated, and only the latter is nitrated, pure 1- chloro-2,4-dinitrobenzene being obtained. 

Apart from skin injuries the symptoms of poisoning by chlorodinitrobenzene are similar to those produced by dinitrobenzene, namely general bodily weakness, cyanosis, a decrease of the number of red blood cells, disturbances in the functioning of digestive organs and heart failure. Treatment and recovery sometimes prove most difficult especially with regard to the digestive tract and the heart, whereas skin lesions are relatively easier to heal. 

Other impurities which may be present in chlorodinitrobenzene are chloro-nitrobenezenes, as products of an incomplete nitration, m- dinitrobenzene formed from benzene present in the chlorobenzene Mid chloropicrin. 

At the Griesheim Woiks the following process was applied for nitrating chlorobenzene to o- mid p- chlorodinitrobenzenes. A cast iron nitrator is charged with 6530 kg of a nitrating mixture of the composition ... 

The nitration of chlorobenzene to chlorodinitrobenzene without separating the isomers of chloronitrobenzene is accomplished in two successive stages in the same nitrator. 

Chlorodinitrobenzene forming the upper layer is washed with warm water, then with a warm dilute solution of sodium carbonate and again with warm water, until entirely free from acid. Then it is dried by heating under reduced pressure in a 20 m3 tank. 

From 100 parts of chlorobenzene 175 parts of chlorodinitrobenzene with a melting point of 47.6°C is obtained, which corresponds to 97.5% of the theoretical yield. 

As Desvergnes [18] reports, nitration by this method was effected in the following way 100 parts of chlorodinitrobenzene were dissolved in 200 parts of 40% oleum. A mixture of 400 parts of anhydrous sulphuric acid and 300 parts of 94% nitric acid was added to the solution. The whole was heated to 150°C with stirring, this temperature being maintained for 3 hr longer. After cooling the mixture was left for crystallization, filtered and the product was washed with cold water. 

Desvergnes suggests a mixture of 560 parts of sulphuric acid (100%) and 150 parts of nitric acid (93%) for the nitration of 100 parts of chlorodinitrobenzene dissolved in 200 parts of 40% oleum at 150°C. 

Picryl chloride is toxic. It acts in much the same way as chlorodinitrobenzene, but is slightly less poisonous. 

It can be seen from the above that the explosive properties of chlorodinitrobenzene are slightly inferior to those of dinitrobenzene. 

Experiments with chlorodinitrobenzene in mixture with picric acid for filling shells have given no satisfactory results. 

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